In Different World with Naruto System (WN) - Chapter 30 Selling Magical beasts’ core.

What if Magic has always existed ever since the beginning of the Earth we are living on, but history has been written in order to hide these facts. What if the prosperous and well-known people in history is actually a mage?

Enter a magic academy, rule your country. Be at the pinnacle of life! Join me in the journey of Emery and the others in the world of Knights and Magic as he becomes the Earth's Greatest Magus.

Luis, a poor 17-year-old boy, tries his luck at becoming an Awakener to change his fate. However, his dreams are shattered when he fails to awaken a Special Spirit and is instead saddled with a 5 million dollar debt by their planet's colonizers, the Flying Star Empire.His life seemed doomed—until a mysterious system suddenly appeared in his head: The Monster Transformation System. It gave him the power to transform into any monster or animal he had ever seen.From a cat to an eagle, even a horse, Luis begins to understand that his power may not come from Spirit... but from the ability to become any monster.

Qin Chen crossed into Taiyi Holy Land as a sweeper, and at the age of sixteen awakened the system. As long as he signed in at different places, he could get different rewards.

Sign in at the Land of Emperor Ruins and get the world’s No. 1 Chaos Holy Body and the Chaos Emperor Sutra!

Sign in to seal the magic land and get the quasi-emperor soldiers!

Sign in at the Refining Hall and get the God-level Refining Technique!

Sign in at the medicine garden and get the medicine of immortality!

Sign in at the Imperial Palace and get the Emperor-level forbidden magical power ‘Resurrection from the Dead’!

…

Qin Chen thought that he would just sign in silently until the world was invincible.

One day, the relics of the Great Emperor will appear in the Holy Land, all the holy places, families, and ancient dynasties have come, and there will be an unparalleled demon king in the relics, killing countless powerhouses, ruling the world, and wanting to destroy the Holy Land.

In desperation, Qin Chen could only walk out, slapped the Demon King to death, and sighed: “I just want to be a sweeper and sign in silently. Why do you force me to take action?”

- Description from novelbuddy

The protagonist fell asleep while playing an online game. However, he awoke in a strange world with his game character’s appearance. In a state of shock, he noticed that he was equipped with nothing but his strongest weapon and armor. To make matters worse, our hero’s appearance was changed by the special avatar skin『Skeleton』when he entered this new world. The protagonist wanted to live without drawing attention, but he got acquainted with the dark elf Ariana and received her request.